Discharge electrode



P 1958 R. G. STREUBER 2,852,093

DISCHARGE ELECTRODE 4 Sheets-Sheet 1 Filed April 16, 1956 INVENTORRUDOLF G. STREUBER BY Aw/zymz/ ATTORNEY Sept. 16, 1958 R. s. STREUBER2,852,093

DISCHARGE ELECTRODE Filed April 16,, 1956 4 Sheets-Sheet 2 y INVENTORRUDOLF s. STREUBER BY w 4/7M ATTORNEY Sept. 16, 1958 R. G. STREUBER2,852,093

DISCHARGE ELECTRODE Filed April 16, 1956 v 4 Sheets-Sheet 3 a n L I IT IW I 46 I i q if so 4e 44 42 I INVENTOR RUDOLF G. STREUBER ATTORNEY Sept.16, 1958 R. G. STREUBER 2,852,093

DISCHARGE ELECTRODE Filed April 16, 1956 4 Sheets-Sheet 4 INVENTORRUDOLF G. STREUBER ATTORNEY United States Patent DISCHARGE ELECTRODERudolf G. Streuber, Bridgewater Township, Somerville, N. J., assignor toResearch-Cottrell, Inc., Bridgewater Township, Somerset County, N. J., acorporation of New Jersey Application April 16, 1956, Serial No. 578,281

1 Claim. (Cl. 1837) This invention relates to electrical precipitationapparatus and more particularly and specifically to new and improveddischarge electrode assemblies and to the individual dischargeelectrodes thereof.

Discharge electrodes for precipitation apparatus have been constructedwith ribbon-like configurations and have been individually suspendedwithin precipitator structures. However, these ribbon-type dischargeelectrodes have been susceptible to several operational disadvantagessuch as the tendency to form hot spots on the electrode, poor coronaeffect, sailing action of the electrode, and arcing and back coronadischarge caused by sailing; all of which disadvantages havesubstantially reduced their eificiency.

It is, therefore, a general object of this invention to provide a newand improved discharge electrode structure including a ribbon-likeelectrode for the purpose of obtaining the advantages of such anelectrode configuration which are well known in the art, yet providingan electrode of the ribbon type which avoids those disadvantagesinherent in prior ribbon electrodes.

An object of this invention is to provide a ribbon-type dischargeelectrode which permits the operation of an electrical precipitator atmaximum efficiency and with the minimum of problems heretofore inherentin ribbontype electrode assemblies.

A further object of this invention is the provision of a ribbon-typeelectrode which is so constructed as to obtain the maximum corona effectWhile avoiding the creation of hot spots and arcing within theprecipitation zone.

A still further object of this invention resides in the provision of aribbon-type discharge electrode for electrical precipitation apparatuswhich enablesthe attainment of corona discharge at minimum potentialrequiremerits and potential requirements lower than those heretoforerequired with prior round wire or ribbon-type electrodes.

Another object of this invention is the provision of a ribbon-typedischarge electrode which is equally effective when incorporated inprecipitation apparatus employing either tube or plate type collectingelectrode structures.

Still a further object of the invention is the provision of ribbon-typedischarge electrodes in combination with a rigid supporting frame whichtautly suspends the electrodes within the precipitator and prevents themfrom swaying or blowing out of spaced relationship with the collectingelectrode assembly.

Another and still further object of the present invention is theprovision of ribbon-type electrode structures and supporting framestherefor wherein the electrodes are readily adapted to stiffeningorcrossbracing intermediate their length for the. purpose of reducingpossible sail eifect of the electrode without reductionin etficiency ordisturbance of corona effect incurred through the use of. suchstiflening or brace members.

Yet. another object and advantage of thisinvention is (d the provisionof a new and improved ribbon-type discharge electrode having an evenlycorrugated configuration providing evenly and alternately spaced edgesbetween the angular segments thereof forming corona discharge Zoneswhich maintain uniform, effective spark distance throughout the entirelength of the electrode.

Still another object and advantage of this invention is the pro-visionof a new and improved ribbon-type discharge electrode having angularalternate corrugations throughout a substantial portion of its lengthwhich is quickly and easily assembled in or removed from theprecipitator apparatus by reason of its novel combination with a rigidsupporting frame for the electrode located within the precipitatorapparatus.

Another object and advantage of this invention is the provision of acorrugated, ribbon-type discharge electrode in combination with a rigidsupporting frame wherein the frame tautly supports the electrode withinthe precipitator apparatus thereby eliminating the necessity ofutilizing weights for maintaining electrode alignment, While at the sametime the structure of the electrode has sufiicient inherent resilienceto permit elimination of the costly spring elements heretofore requiredfor mounting and suspending such electrodes within precipitationapparatus.

Still a further object and advantage of this invention is the provisionof a new and improved ribbon-type electrode which is of extremely simpleand inexpensive design and manufacture and which is efiicient anddurable over extended periods of use.

Still other objects and advantages of this invention Will become morereadily evident to those skilled inthe art when the following generalstatement and description are read in the light of the accompanyingdrawings.

The nature of the present invention may be stated in general terms asrelating to a ribbon-type discharge electrode in combination with arigid rectangular frame wherein the electrode comprises an elongatedconductive strip of ribbon-like configuration having hook means at eachend for engaging about the opposite end pieces of the rigid frame, saidribbon-like member being corrugated throughout a substantial portion ofits length interrnecliate its ends, said corrugations taking the form ofalternate angular segments formed to extend for equal distance.outwardly from the longitudinalcenterline of the strip, and the angularrelationship of said segmentsgbeing equal throughout its corrugatedlength.

Referring now to the accompanying drawings in which like numeralsdesignate similar parts throughout the several views:

Fig. 1 is a vertical section through an electrostatic precipitatorhaving the discharge electrodes constituting the present inventionlocated therein.

Fig. 2 is a vertical section through a precipitator apparatus taken atright angles to Fig.

Fig. 3 is a pictorial illustration of a discharge electrode conformingto the present invention.

Fig. 4 is a fragmentary view similar to Fig. 2 illustrating a modifiedform of the electrode structure.

Fig. 5 is a view similar to Fig. 4 showing stilla further modificationof the electrode structure including antiswing weights intermediate theelectrode length.

Fig. 6 is a fragmentary pictorialview illustrating a weighted segment ofthe electrode disclosed in Fig; 5.

Fig. 7 is an enlarged side elevation ofthe weighted segment disclosed inFig. 6.

Fig. 8 is an elevational view of a modified form of the electrodeassembly including a stabilizing brace.

Fig. 9 is a vertical section taken on line9-9, Fig. 8..

Fig. 10 is an enlarged fragmentary section disclosing the braceattachment to the modified electrode; disclosed in Fig. 8..

usual hopper bottom 16 for receiving and discharging precipitatedmaterials from the housing.

Plate-type collecting electrodes 18 are supported longitudinally of thehousing between the gas inlet and the gas outlet in parallel spacedrelationship. The collecting electrodes are suspended from topsupporting bars 20 which in turn are supported from brackets 22 securedto the inner walls of the housing adjacent its upper end.

Associated with the spaced parallel collecting plate members is aplurality of discharge electrodes 24 which are arranged in spacedrelationship in parallel rows intermediate the collecting plateelectrodes 18. In the present embodiment a high tension frame 26 issuspended transversely above the upper ends of the spaced collectingplate electrodes from an insulator support 28 mounted in conventionalmanner within a housing 30 carried on the top of the precipitatorhousing.

Associated with the high tension frame 26 is a plurality of rigidrectangular frames 32 each of which is suspended vertically from thehigh tension frame in parallel spaced relationship equidistant betweentwo spaced collecting electrode plates 18. The frame 32 is somewhatgreater in length vertically of the housing than the vertical length ofthe collecting electrodes 18 so that when positioned within the housingthe frame extends for a spaced distance above and below the upper andlower ends of the collecting plates. Associated with each rigid frame 32is a plurality of discharge electrodes 24 which are arranged in equallyspaced relationship longitudinally of the upper and lower end members ofthe frame and which are positioned to extend vertically within thehousing intermediate the upper and lower endmernbers of the frame. Eachof the collecting electrodes 24 takes the form of an elongated metallicribbon formed from a flat sheet with each of the ribbon members beingevenly corrugated as at 34 through a substantial portion of its lengthintermediate the extended ends thereof wherein the corrugated portion ofeach electrode is formed by alternately crimping the opposed flat facesthrough a substantial portion of its length in such a manner as topresent on opposite sides thereof alternate folded edges 36 extendingtransversely of the ribbon with alternate edges on opposite sides orfaces of the ribbon projecting equidistant outwardly from the centerlineof the ribbon established between the uncorrugated portions 38 at eachend thereof.

For example, a metallic ribbon of light gauge stainless steel or thelike of approximately to 4-inch wide and of about 20 gauge may becorrugated by passing the strip through suitably faced rolls, or such asheet could be stamped, to provide the corrugations. Corrugationsapproximately of an inch in depth to provide each peak portion, orfolded edge 36 as described, to extend inch outwardly from thelongitudinal centerline of fi-inch ribbons as established between theflat uncorrugated end portions has been found to give satisfactoryresults. For a ribbon 42-inch wide, the depth of the corrugations wouldbe about A3 to about /2 inch.

However, it will be understood that the depth of corrugation can bevaried to fit variations in plate spacings between top and bottomsections of a plate.

In the embodiment disclosed in Figs. 1, 2 and 3, the extended ends ofeach ribbon electrode are provided with a hook member 40 formedintegrally therewith and adapted to detachably engage the upper andlower end members of the rigid frame 32 for the purpose of releasablymounting the electrode longitudinally of the frame. By providing theelectrode of an over-all length slightly less than the over-all verticallength of the frame 32 it becomes necessary to longitudinally flex theelectrode, the corrugated portion of which provides limited longitudinalflexibility, to tautly mount the electrode on the frame under constantlongitudinal tension. By mounting the electrode on the frame underlongitudinal tension the electrode, in addition to being held firmly inplace, is deterred from swaying movement or sailing effect common inprecipitator apparatus employing ribbon-like electrodes and, at the sametime, expansion of the electrode due to increased heat in theprecipitator will not cause the electrodes to sag.

From the foregoing, it can be readily seen that a new and uniquecollecting electrode structure has been provided including a ribbon-typeelectrode having a corrugated section throughout a substantial portionof its length which is positioned intermediate the collecting plates ofelectrical precipitation apparatus. The folded edges on opposite sidesof the ribbon electrode are normally disposed opposite the collectingplates 18 and provide highly efficient corona discharge points formaintaining a maximum corona discharge efiiciency within theprecipitation field and the uniformity of corrugation and extension ofsuch corona points equidistant on opposite faces of the ribbon-typeelectrode provide a uniform distance between the discharge points onopposite sides and the collecting plates associated respectivelytherewith.

It is known that efficient corona discharge may be obtained atconsiderably lower potentials from sharp points or edges; therefore, thecorrugated electrode structure herein disclosed enables the utilizationof lower potentials than have been heretofore usable in precipitationapparatus employing fiat or round wire discharge electrodes.

At the same time it is seen that utilization of a rigid frame mountingthe discharge electrodes in the manner described tends to avoid theproblems of swaying and sailing effect which are usually inherent inprior structures which have heretofore utilized weights or the like onthe lower extended ends of the electrodes for the purpose of maintainingelectrode alignment.

In Fig. 4 of the drawings there is shown a construction wherein theplate-top collecting electrodes 18 are provided at equally spaced pointsintermediate their vertical length with stiffening ribs 42 which extend,in conventional manner, transversely of each plate and provide athickened plate section at their point of attachment or formation whichproduces projecting surfaces 44 outwardly from either face of thecollecting plate 18. Where such a stiffening rib is provided in thecollecting plates of precipitation apparatus a discharge electrode 46formed basically in the manner and configuration of the electrode 24heretofore described is utilized by locating it in conventional mannerintermediate two parallel spaced collecting plates 18. However, thecorrugated section or portion of the electrode 46 is modified byproviding a flat segment 48 in the electrode immediately adjacent theprojected surface 44 of the stiffening rib 42 in the collecting plate.The extended length of the fiat segment 48, which lies on the centerlineintermediate the flattened end portions of the electrode, is determinedby the extent of projection of the surfaces 44 outwardly from the normalplane of the face of the collecting plate electrode. The extent ispredetermined so as to prevent any reduction in the sparking distancebetween the discharge electrode and the projected surface areas 44 ofthe rib and is such as to maintain the distance between the flattenedsegment and the projected surfaces of the rib as nearly equal aspossible to the normal sparking distance between the folded edges 36 ofthe electrode and the normal plane of the face of the collecting plate.

In Figs. 5 through 7 of the drawings, there is illustrated method andapparatus for attaching to a ribbontype electrode constructed inaccordance with the above described invention anti-swing weightsatspaced intervals longitudinally of the electrode. By providing shortflattened segments 50 in the corrugated section of the electrode atspaced intervals along the electrode length dampening or anti-swingweights taking the form of a pair of identical rhombic blocks 52, eachof which has equal angular converging side walls 54 may be secured toeither side of the flat segment with the corresponding long side of eachmember being seated against the opposite faces of the flat segment.Bolts 56, rivets or the like may be utilized to firmly secure the blocksto the opposite faces of the flat segments. The extended measurement ofeach block perpendicular to the plane of the flat segment is identicalto the distance each of the folded edges 36 is off-set from thecenterline of the electrode thereby maintained between the swing weightand the adjacent collecting plates a sparking distance equal to thesparking distance between each of the folded edges 36 in the corrugatedsection of the electrode.

By utilizing dampening or anti-swing weights constructed in accordancewith the foregoing disclosure and assembled in combination with anelectrode of the type defined, uniformity of corona discharge ismaintained throughout the length of the electrode while at the same timeswaying and sailing effect are substantially eliminated.

In Figs. 8 through 10 of the accompanying drawings, there is disclosedmethod and apparatus for providing a stiffening brace for the dischargeelectrodes at a point intermediate their length. There is also discloseda modification of the corrugated electrode to accommodate a stiffeningbrace in such a manner as to avoid the creation of any non-uniformity inthe spark distance between any point on the electrode and an adjacentcollecting plate.

In these views there is shown a ribbon-type electrode 58 having a fiatsegment 60 therein at a point equidistant between its ends wherein theflat segment 60 is provided centrally of its length with an angularcrimped section 62 outwardly of one face of the segment. The angularityand dimension of the crimped section 62 substantially coincides with theangularity and dimensions of a diamond-shaped tubular rib or brace 64,two sides of which are received and secured by rivets 66 or the like inthe crimped section 62 of the fiat segment 60. The extended ends of therib or brace are rigidly secured as at 68 to 6 is provided between theapex of the crimped section and the oppositely extending corner 70 ofthe rib 64 and the collecting plates adjacent thereto which is equal tothe spark distance maintained between the folded edges 36 on each sideof the ribbon-type electrode and the collecting plate surfaces adjacentthereto.

Thus, it can be seen that a rigid brace or stitfening rib has beenprovided for the collecting electrodes to deter them from sailing orswaying within the precipitator housing while maintaining uniform coronadischarge throughout the length thereof.

In Fig. 11 of the drawings a ribbon-type electrode 24 constructed inaccordance with the present invention is shown suspended centrallywithin a tubular collecting electrode 72. In this embodiment of theinvention it will be seen, as illustrated by broken line that coronadischarge will occur between the electrode 24 and substantially allsurfaces of the tubular electrode 72 thereby providing a highlyeflicient precipitation field. It will be evident that dampening oranti-swing weights can be utilized with the electrode 24 within atubular collecting electrode in the same manner heretofore described andwith the same advantageous results.

Thus having described the novel construction and new and useful resultsobtained from the present invention, what is desired to be claimed is:

In combination with an electrical precipitator, an extended surfaceelectrode, complementary discharge electrodes comprising elongatemetallic ribbons being corrugated laterally of the opposed fiat faces toprovide a continuous series of substantially symmetrical ridges andgrooves substantially throughout the ,length thereof, supporting meansprovided to maintain said discharge electrodes in substantially parallelspaced relationship relative to said extended surface electrode, and arigid rib member secured between opposed sides of said supporting means,said rib member registering with and being secured in the corrugationsformed in said discharge electrodes intermediate opposed sides of saidsupporting means.

References Cited in the file of this patent FOREIGN PATENTS 487,444Germany Dec. 12, 1929 694,603 France Sept. 16, 1930 718,611 France Nov.4, 1931 868,429 France Sept. 29, 1941

